Hi Sergey,
>The index "design" is bad. Try

SET EXACT OFF
SEEK transform(13609,'99999999')
SCAN WHILE transform(de_sysnum,'99999999')+transform(de_histnum,'9999') = transform(13609,'99999999');
       FOR de_sysnum == 13609
   **** Do something
ENDSCAN

...
>>active index is:
>>transform(de_sysnum,'99999999')+transform(de_histnum,'9999')

I'ld have proposed

SET EXACT OFF
SEEK transform(13609,'99999999')
SET EXACT ON
SCAN rest WHILE de_sysnum = 13609
      **** Do something
ENDSCAN

Since the controlling index already forces the order. Am I overlooking something ?
The dsik movement optimization which is the main optimization should still be identical,
but why the 2 checks ? And "==" used with numerical fields was definitly slower
in tests done a long time ago - haven't checked recently.

regards

thomas